Provided is an etching-before-packaging horizontal chip three-dimensional system level metal circuit board structure comprising a metal substrate frame; the metal substrate frame is provided with base islands and pins therein; the front faces of the base islands are provided with chips; the front faces of the chips are connected to the front faces of the pins via metal wires; conductive posts are disposed on the front faces or back faces of the pins; the peripheral areas of the base islands, the areas between the base islands and the pins, the areas between the pins, the areas above the base islands and the pins, the areas below the base islands and the pins, and the exteriors of the chips, the metal wires and the conductive posts are all encapsulated with molding compound.